%Tc@s/dZddlmZedZdZdS(sDA log function that returns negative infinity for log(0) or log(x<0)i(tlogs -infinitycCs:d}yt|}Wnttfk r5t}nX|S(sCalculate the log without raising an error ARGUMENTS: a - the value to calculate the log of RETURNS: log(a) if it is defined negative infinity otherwise (when a <= 0) N(tNoneRt ValueErrort OverflowErrortnegInf(tatln((sU/public2/ftp/pub/ccp4/6.5/ccp4-6.5/lib/python2.7/site-packages/coot/rcrane/safelog.pyRs  N(t__doc__tmathRtfloatRR(((sU/public2/ftp/pub/ccp4/6.5/ccp4-6.5/lib/python2.7/site-packages/coot/rcrane/safelog.pyts